Abstract: The operation of an open ring-type baking furnace for the production of shaped carbonaceous bodies and having at least partly grouped fire shafts is such that during the fire reversal phase the negative pressure is regulated in each fire shaft in the transverse walls near the fire reversal units. This regulation takes place, depending on the position of the pre-heating zone, at the transverse wall on the suction unit side or on the baking side of the furnace. In particular in combination with process control means the process leads to a uniform product quality independent of the position of the said body in the furnace.